The collection of air freight and mail in commercial aviation (scheduled and non-scheduled) includes domestic and foreign aircraft, which take off or land at the six international Austrian airports (Vienna, Graz, Innsbruck, Klagenfurt, Linz and Salzburg). Flights with passengers, freight and mail transport and empty leg flights in domestic and international traffic are collected where the start or landing is performed in Austria. Domestic flights are recorded several times because the reported values of the individual airports are counted. The information on air freight transported refers to goods that were actually transported by aircraft. Data is collected and published monthly. Replacement air freight traffic (transport by truck between airports) is also collected once a year.